The dose of many medicaments is dependent on the weight of the patient. However, it is currently difficult to measure a patient's weight quickly and accurately where they are unable to stand. The efficacy of drugs is reduced if the wrong dose is administered, and the risk of side-effects is increased.
Upon admission to hospital many patients are unable to support their own weight due to unconsciousness or due to suspected injury, in particular suspected back, neck or leg injuries. Moreover, where patients are admitted with chest pain or breathlessness, hospital procedure is for such patients to remain in a lying or sitting position. It is not possible for such patients to be weighed on conventional weighing scales as these require the patient to stand. Although weighing devices such as hoists are available in hospitals, these involve placing the patient in the hoist and lifting the patient off the bed/trolley in order for a weight to be taken. This is time consuming, requires suspending the patient, with consequent safety issues e.g. hoists can topple if not used appropriately. Alternatively, floor scales can be used which weigh both patient and trolley. Floor scales tend to be extremely heavy, thus non-portable, and need to be large enough to accommodate a trolley. Both the aforementioned methods require considerable space, which is often at a premium in hospital emergency areas.
Upon admissions into hospital, children's weight is typically estimated using generalized calculations dependent on the child's age. Weight is currently commonly estimated using the equation:Weight (kg)=child's age+4×2.
However, the weight of children of the same age can greatly differ. This is an inaccurate method of calculating weight, and this can prove dangerous where such calculations are used to calculate doses of medicaments including opiates.
In addition, where there is limited or no access to scales or where drugs must be administered quickly, adult weights are also frequently estimated. Research has shown that these estimates are often inaccurate, particularly where medical staff are estimating the weight of a patient, rather than the patient providing an estimate of their own weight.
It is also difficult to measure a patient's weight when they refuse to keep still for periods during the weighing process, for instance where the patient is a child, or where the patient is confused, drunk and/or uncooperative.
Some medicaments must be administered within a maximum time from an event. For instance, the drug for stroke must be given within 4½ hours from the onset of symptoms, with the hospital standard in the UK as 1 hour from patient admission. Accordingly, time is of the essence during the admissions procedure. However, weighing procedures for patients who are unable to support their own weight can be lengthy. The use of a hoist is commonly associated with a weighing procedure of up to 15 minutes or longer. Providing a faster procedure for weighing suspected stroke victims would provide significant advantages. Furthermore, patients being admitted with a serious condition such as stroke are vulnerable and often fearful of what may happen next. To place such patients in a hoist can greatly add to their distress.
The patient transfer device PatSlide® is commonly used to transfer patients from one surface to another in hospitals, for instance from trolleys to beds. Other similar devices exist. This patient transfer device consists of a flexible sheet of plastic with good slip properties on its surface, enabling patients to be transferred smoothly and easily with minimal risk of back strain to hospital staff. The use of these devices in hospitals is a well-accepted and common procedure.
The weighing apparatus of the present invention provides a quick, accurate weight measurement for patients who cannot support their own weight and this may take place during the procedure of transferring the patient from one surface to another, for instance from a hospital trolley to a bed. The weighing apparatus of the present invention is thus particularly suitable for use in a hospital admissions ward where medicaments must be prescribed quickly, and such prescription is dependent on the weight of the patient. In hospital admissions wards, diagnosis has not yet occurred and a significant number of patients cannot support their own weight on conventional weighing apparatus.